In a process of manufacturing a semiconductor substrate (hereinafter, referred to simply as a “substrate”), conventionally, various processings are performed on a substrate by using a substrate processing apparatus. By supplying a chemical liquid onto a substrate having a surface on which a resist pattern is formed, for example, a processing such as etching or the like is performed on the surface of the substrate. Further, after the etching process is finished, performed are a process of removing the resist from the substrate by supplying a removal liquid onto the substrate and/or a process of cleaning the substrate by supplying a cleaning liquid onto the substrate.
In this type of processing performed on a substrate by using a processing liquid, when the processing is performed under the environment where oxygen exists, such as in the atmosphere, the oxygen sometimes produces an adverse effect on the substrate. There is a case, for example, where the oxygen is dissolved into a chemical liquid used for the processing and the chemical liquid comes into contact with a surface of the substrate, to thereby produce an adverse effect on the surface of the substrate. Particularly, in a case where a metal film is formed on the surface of the substrate, for example, when the oxygen is dissolved into the processing liquid which is a removal liquid, to thereby increase the oxygen concentration in the processing liquid, the metal film on the substrate is sometimes oxidized by the processing liquid. Since a metal oxide is etched by the processing liquid, this causes a film loss of the metal film. It is required that such an adverse effect (oxidation of the metal film) should be prevented as much as possible. Then, in a substrate processing apparatus disclosed in Japanese Patent Application Laid-Open No. 2010-56218, provided is a cutoff member which faces a substrate held by a substrate holding part. The cutoff member includes a substrate facing surface which faces the substrate and a peripheral wall portion protruding from the perimeter of the substrate facing surface toward the substrate holding part. In the substrate processing apparatus disclosed in Japanese Patent Application Laid-Open No. 2010-56218, by providing the cutoff member, an atmosphere of the surface of the substrate is cut off from an atmosphere outside the cutoff member, and an increase of the oxygen concentration in the atmosphere of the surface of the substrate is thereby prevented. Further, Japanese Patent Application Laid-Open No. 2011-216607 and US Patent Application Publication No. 2012/0103522 disclose a substrate processing apparatus having a sealed chamber. In the substrate processing apparatus having the sealed chamber, it is possible to easily reduce the oxygen concentration in an atmosphere around the substrate. In the substrate processing apparatus disclosed in Japanese Patent Application Laid-Open No. 2011-216607 and US Patent Application Publication No. 2012/0103522, a nozzle for supplying a processing liquid onto a substrate is further provided in an internal space of the sealed chamber.
Japanese Patent Application Laid-Open No. 2003-45838 discloses a substrate processing apparatus which includes a spin chuck for rotating a wafer, a cutoff plate provided above the spin chuck, a processing cup for accommodating the spin chuck, and a processing liquid nozzle for supplying a processing liquid onto the wafer. Above the processing cup, provided is a splash guard for preventing the processing liquid from splattering from the wafer to the outside. In the substrate processing apparatus disclosed in Japanese Patent Application Laid-Open No. 2003-45838, by discharging a cleaning liquid toward an upper surface of the cutoff plate being rotated, the cleaning liquid is shaken off and spatters from a periphery of the cutoff plate and the processing liquid adhered to the splash guard is rinsed off by the cleaning liquid.
In the substrate processing apparatuses disclosed in Japanese Patent Application Laid-Open No. 2010-56218 and Japanese Patent Application Laid-Open No. 2003-45838, since the inside of the cutoff member is not completely isolated from the outside thereof, there is a limitation in reduction of the oxygen concentration in the atmosphere of the surface of the substrate (the atmosphere on the substrate). Further, there is also a limitation in rapid reduction of the oxygen concentration in the inside of the cutoff member. Then, there is a possible method in which the substrate is disposed in a chamber (processing chamber) and an inert gas or the like is supplied into the chamber, to thereby reduce the oxygen concentration in the atmosphere around the substrate. However, in a case, for example, where after loading the substrate in the inside of a chamber body, an upper opening of the chamber body is closed by a chamber cover to thereby form the chamber and the inert gas or the like is supplied into the sealed chamber, to thereby bring the chamber into a low oxygen state, there is a possibility that a mist of and/or fumes of the processing liquid which is supplied onto the substrate inside the chamber are adhered to an inner surface of the chamber cover which covers an upper portion of the substrate. Further, in the substrate processing apparatus, the substrate is dried after the processing performed on the substrate by using the processing liquid. Therefore, it is preferable that a space in which the substrate is dried should be kept clean. It is not easy, however, to keep clean the inside of the chamber in which the processing is performed by using the processing liquid.
Further, in the substrate processing apparatus in which a discharge part (nozzle) is provided inside the chamber, a liquid such as the processing liquid or the like is adhered around the discharge part. In this case, when droplets of the liquid fall onto the substrate during unloading or the like of the substrate, the substrate is contaminated. Though there is a possible method in which the discharge part is dried by supplying a gas into the inside of the chamber, this method is an inefficient one since the chamber for processing a substrate has a large size and this needs an increase of gas flow rate.
Furthermore, in order to efficiently perform the processing on a substrate, it is preferable to rapidly and sufficiently bring a substrate environment into a low oxygen state after loading the substrate into the chamber. Since the chamber for processing a substrate has a large size, however, this needs an increase of gas flow rate, or the like, in order to rapidly bring the inside of the chamber into a sufficient low oxygen state after loading the substrate into the chamber.